" But what do you say to this argument (help me with it): ghosts are, as it were, shreds and fragments of other worlds, the beginning of them. A man in health has, of course, no reason to see them, because he is above all a man of this earth and is bound for the sake of completeness and order to live only in this life. But as soon as one is ill, as soon as the normal earthly order of the organism is broken, one begins to realise the possibility of another world; and the more seriously ill one is, the closer becomes one’s contact with that other world, so that as soon as the man dies he steps straight into that world. I thought of that long ago. If you believe in a future life, you could believe in that, too. "

― Fyodor Dostoevsky , Fyodor Dostoyevsky: The Complete Novels (Centaur Classics)